Close button not showing on jquery ui dialog form

This problem might occur when you call jquery ui css file local system. The problem is your script is able to findat provided url given in css file. To fix the error you need to made change to two lines in css file.
Change the text with in red  at line number 823 and 840 with

https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2lhmuG3GfNdP1UeMC2iLdF67anzBF0q71xpd7WwTPkfthDDQJAKB6qOhSvUnfOFyEbXjmOYIL48MHvuiaWY15QcbPYHjFdLD-I8EcA-co_7t9QX0hC7FjBCnUxbMpdUqUfqP8INUh6KI/s1600/close.gif

Corrected statement will be :

background: #dadada url(https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2lhmuG3GfNdP1UeMC2iLdF67anzBF0q71xpd7WwTPkfthDDQJAKB6qOhSvUnfOFyEbXjmOYIL48MHvuiaWY15QcbPYHjFdLD-I8EcA-co_7t9QX0hC7FjBCnUxbMpdUqUfqP8INUh6KI/s1600/close.gif ) 50% 50% repeat-x;
1. At line number 823

.ui-widget-header .ui-state-default {

border: 1px solid #d3d3d3;

background: #e6e6e6 url(images/ui-bg_glass_75_e6e6e6_1x400.png) 50%   50% repeat-x;

font-weight: normal;

color: #555555;

}

2. At line number number 840

.ui-widget-header .ui-state-focus {
    border: 1px solid #999999;
    background: #dadada url(images/ui-bg_glass_75_dadada_1x400.png) 50% 50% repeat-x; 

     font-weight: normal;
    color: #212121;
}